The invention relates to a device for thermosurgery.
In thermosurgery, biological tissue is heated by the introduction of treatment energy in order to achieve a specific therapeutic goal by denaturing the treated tissue. In particular, it is intended in thermosurgery to achieve coagulation or ablation of local tissue zones, for example on the interior wall of the cardiac ventricles, on the cardiac valves, on cardiac veins and arteries or other blood vessels of the human or animal body. Thermosurgery may be used on the heart for example to treat cases of arrhythmic or tachycardia. It will be understood that the field of application of the thermosurgical device according to the invention is not restricted to cardiac treatment. In principle, the device according to the invention is suitable for the thermosurgical treatment of any desired areas on or within the body.
Monopolar and bipolar applications are known in electrical HF thermosurgery. In both types of treatment, the high frequency alternating current used for treatment is introduced into the body via an application electrode, which is placed in the immediate vicinity of the tissue area to be treated. In the bipolar method, the circuit is completed by one or more planar counter-electrodes which are laid externally on the skin of the body remotely from the application electrode. The effective electrode area of the counter-electrodes is large in comparison with that of the application electrode, for which reason the current density at the counter-electrodes is low and there is no need to fear skin charring there under normal circumstances (i.e. good contact of the counter-electrodes with the skin).
The situation changes if the counter-electrodes become partially detached from the skin. In this case, the current density rises sharply in the areas of the counter-electrodes still in contact with the skin, so correspondingly increasing the risk of skin charring. Thermosurgical treatments may very easily last for several hours. Patient movement and sweating may impair the quality of the contact between the counter-electrodes and the skin. Experience has shown that, as treatment time increases, so too does the risk that the electrical contact between the counter-electrodes and the skin becomes poorer.